What are the main differences between OpenVPN open source and OpenVPN Access Server?

Features	OpenVPN open source	OpenVPN Access Server
TLS encrypted VPN tunnels	✓	✓
Graphical web interface		✓
Automated certificate creation		✓
Pre-configured client software		✓
Easy deployment		✓
Pre-built virtual appliances		✓
Simple user management		✓
High-availability failover solution		✓
Multi-node cluster solution		✓
Easy scalability		✓
Configurable encryption ciphers	✓	✓
LDAP support included		✓
RADIUS support included		✓
Multi-daemon mode		✓